In distribution of feature films in recent years, there is a tendency for a plurality of streams to be multiplexed into a single digital stream, and particular importance is placed on functions for selecting between the streams. There is an increasing number of streams in order to be compatible with various combinations of codecs, channel numbers, and language attributes.
Here, in codec, when the types are AC-3 (2 ch), AC-3 (5.1 ch), and DTS (5.1 ch) and the language attributes are Japanese and English, an audio stream is multiplexed into a digital stream so as to have a total of six combinations. Since a specified number system is attached to these audio streams, causing the playback device to perform an operation to select, from among the plurality of audio streams, and play back an audio stream having the same number as the number set in the status register of the playback apparatus enables always playing back an audio stream in correspondence with a determined codec and language attribute.
This set value in the status register can be an initial setting at the time of factory shipment, or the user can update the status register afterward. Note that Japanese Patent Application Publication No. 3128220 discloses conventional technology for fulfilling the playback function described above.